Method of manufacturing dies



June 17, 1930. LQKELLER l 1,764,633;

METHOD OF MANUFACTURING DIES Filed May 22 1925 I mre/2/0/ Freda/70H.lflq/ef omTEDfsTATEs Patented June 1 7,

PATENT oFFicEfi;

FREDERICK tAwREN'c KELLER, or CHICAGO, ILLINOIS, AssrGNoRi "11o WESTERNEnEcrRrccoiiiranv, ,IivooRroRAr noE NEW YoRK, 1a. Y., A coREo ATIoN E"nEw YOR Application filed. May 22,,

This invention'relates to methods of manufacturing dies, and moreparticularly to methods of manufacturing blanking dies.

An object'of the invention is to simplify and improve the constructionof dies and the'rebyreduce theamount of labor involved in the finishingof the openings in such dies.

The invention contemplates the swaging of the material of which a die is'made, around a mandrel and then withdrawing the mandrel to leaveanopening corresponding to theshape of the mandrel. In accordance with oneembodiment of theinvention, the opening in the blanking die is madesomewhat larger than required and the opening is then reduced to theproper size by subjecting the die to a high pressure causing a cold flowof the metal around themandrel which is of the size required for theopening.

It is believed that a better understanding of the invention may be hadby reference to the following description taken in conjunction with theaccompanying drawing showing an apparatus by means of which theinvention may be practiced, and in which Fig. 1 is a fragmentary planview of a die and mandrel associated with a yoke as 7 they appear in theinitial stage of the swagtelephone and other apparatus.

ing process;

Fig. 2 is a fragmentary sectional view taken on the line 22 of Fig. 1showing in addition portions of the ram and bed of a hydraulic press inposition to press the die into the tapered bore of the yoke, and

Fig. 3 is a reduced plan view of the yoke anddie. 7

Referring to the drawing in which similar reference characters representthe same parts in the various views, the numeral 6 designates a diemember of the typeused 1n punch presses for blanking variously shapedfiat pieces such as are used extensively in The die member illustratedis designed for punching blanks for forming contact springs having theshape ofthe opening in the die.

In order that a punch pressin which such 1 dies are used may operateproperly it is necessary that the outline of the opening in the dieelement conform precisely to the out- 5 "METHOD oE AnUEno'ru nvenIEs192s; seriai No. 110,847."

line of the punch. -Heretofore it has been the practice in some cases tofile theo'pening to its fin'al size manually, involving a great amountofaccurate and skilled labor since these parts are usually made of hardmetals such as carbontool steel. j

According tothe present invention, an opening 11 is made in the diemember slightly larger than a mandrel 12' which consists of arectangular base 4 and a shank5 of hardened carbon tool steel. Nospecialattention is paid to thesizeor the exactness of the outline ofth'eopening in the die except that'it be larger than themandrel. The idealcondition is an opening ranging from 1/200 inch to 1/64: inch larger.than'the arbor. The opening is then reduced to the proper size bysubjecting the dieto a high lateral pressure which is produced byforcing the die downa tapered opening 9=of a yoke 7 of hardened carbontool steel. The yoke has a grip- 20, to facilitate handling it and abandf17 of sheet metal is-provided-aboutthe exterior of the yoke topreventthe yoke fromscatteringif it should burst due to the highpressure. The die member 6 isturned about 7 its outer periphery, with a;beveled; edge having a 3 degree angle whichcorresponds with the slope ofthefrusto-conical opening 9 of the 'yoke, and its size-is such that itsgreatest diameter'is equal to thegreatest diameter of the opening in'theyoke, therefore,- whenthe die is placed in the yoke,'its top surfacewill lie flush face of theyoke.

' The upper part the die has a reduced portion 15 since it hasbeenfoundthat when the dieblank is'made as a regular. frustum there is atendency'for it to buckle and'become distorted due'to thefact that thereis a contraction along the diameter. 1 Whenthe upper portion of the dieis reducedas shown,

this tendency is greatly minimized, since the spacethus provided affordsa place for the. 'metal to flow. i Y

When the die is placed in] the yoke a spiral compression spring 14 holdsthe mandrel in position and as the die is forced down into theyoke by aram 16 of hydraulic withthe top surice the arbor.

As an example in the process of producing a carbon tool steel die 5inches m diameter, a yoke .7 of hardened carbontool steel is placed upona bed 18 of a hydraulic press.

A coating of White lead and oil is applied to 'the' inclined surface ofthe yoke and to the beveled edge of the die and a similar coating isapplied to the mandrel and the Walls of the opening in the'die. 'The'mandrel is then inserted in the die opening and the die is positioned inthe yoke'and pressed down the tapered bore of the yoke about two inchesunder a pressure-of approximately sixty-five tons. During this operationthe thickness of-the'die increases about 11/ 16 inch and the metal ofthe die is forced around the mandrelgiving the required shape and sizeto the opening. After the pressure is removed, the die is forced out ofthe yoke by any suitable means and the mandrel is removed completing thedie.

It will be understood that the embodiment ofthe invention hereindescribed and illustrated' is merely a useful and convenient form of theinvention, which is capable of many other modifications Withoutdeparting from the-spirit and scope'of'the invention;

WVhat-is claimed is:

1. A method of making a .die, which consists of forming a circularbeveled edge around a die blank, reducing the periphery of the die blankat its greatest diameter to prevent buckling, making an opening in thedie blank and reducing the size of the opening by exertingia pressure onthe beveled edge ofthe diegblankto forceithe material arounda memberofthefdesired shape.

2., A method of making a die, which consists of making an opening in thedieblank differing from the required opening, reduce ing the peripheryofthe die blank to-prevent buckling, and alteringtheopening inthe dieblank by causinga 'cold flow-iof the material around the opening.

3. A method of making a die having a plane upper and-lower surface,which consists in forming a frusto-con-ical disk with a reduced portionat its greatest diameter to prevent buckling, making an opening ofpredetermined size through the'body of the disk, placing a member ofthedesired-shape Within the opening, and reducing theopening to a'shapedetermined'bythe memberby causing the material of the disk to flowlaterally into engagement With the member by exerting a radiallyinwardipressure on the. blank.

4. A method of making a die, which consists in forming a disk :having aplane-sun face ,shapingthe sides of the diskto a frustoconical shape,forming aireduced portion at the base of the frusto-conical section,making an opening through the body of the disk, placing a member of thedesired shape in the opening, and'causing the material of the disk tomove substantially in planes parallel to the plane surface of the diskby exerting a radially inward pressure thereon .to change the opening tothe shape of the member.

In Witness whereof I hereunto subscribe my name this 7th day ofMay, A.13.1926. FREDERICK LAWRENCE

